1. Field of the Invention
The present invention relates to hydraulically driven tools and, more particularly, to a motor driven hydraulic tool with a self-regulating variable displacement pump.
2. Prior Art
U.S. Pat. Nos. 5,195,354; 5,111,681; and 5,272,811 disclose motor driven hydraulic tools. U.S. Pat. Nos. 4,956,992; 4,932,237; and 4,774,762 disclose battery operated crimpers. U.S. Pat. Nos. 4,475,374; 4,084,460; 2,343,595; 2,180,979; and 2,158,855 disclose other types of relevant compression tools. U.S. Pat. Nos. 5,113,679; 5,152,162; and 5,195,042 disclose a hydraulic compression tool with an electronic controller, batteries, signal lights, a hydraulic system pressure sensor, and a system for deactivating pumping effect of a pump when a predetermined hydraulic system pressure is reached. The tool has a two stage pump that decreases the volume of fluid pumped by the pump when hydraulic system pressure reaches a predetermined level. Huskie Tools Inc. of Glendale Heights, Ill. sells a portable, hand-held automatic cable crimper sold under the trademark ROBO*CRIMP that uses replaceable, rechargeable battery cartridges. An LED battery power level indicator flashes when five compression cycles remain.